Data storage systems are used to store large volumes of information. As the quantity of information requiring storage continues to increase at unprecedented rates, predicting future storage needs and managing storage infrastructure costs are difficult problems. Accordingly, data storage systems use various techniques to regularly scale up capacity, throughput, and availability of data while reducing system downtime.
Some data storage systems store a plurality of data cartridges in slots within one or more drawers. Such data storage systems include media storage systems or autochangers to automatically change data cartridges in a cartridge reader in response to commands from a controller, enabling access to multiple data cartridges without having to manually position each cartridge in a reader. An autochanger may include one or more different types of cartridge-receiving devices capable of holding cartridges of different sizes and form factors.
These media data storage systems include one or more storage racks or magazines arranged in drawers, rows, or other configurations that supply storage locations for the data cartridges. The data storage system commonly includes one or more cartridge read/write devices to access and store data on the cartridges. Although various operational modes are possible, systems commonly have the read/write device in a fixed location and use a moveable cartridge picker assembly to transport data cartridges between storage racks or magazines and the cartridge read/write devices. The cartridge picker can have a plunge mechanism that engages a data cartridge held within the rack or magazine and withdraws the data cartridge. The data storage system also can include a picker positioner that moves the cartridge picker assembly along the rack for transporting the cartridges between the read/write devices and the racks.
Data storage systems can have a controller, such as a host computer system, central processing unit (CPU), microcontroller, microprocessor, state machine, or other type of processor that manages data access and storage. The controller commonly controls functions of the read/write device and other operational elements of a data storage system.
For example, during operation the controller can issue a request for data contained on a particular data cartridge. A control system associated with the data storage system can actuate the picker positioner to move the picker assembly along the cartridge storage racks until positioned adjacent the selected cartridge. The control system then actuates the plunge mechanism to move the data cartridge from the storage rack to the picker assembly, and moves the picker assembly to a cartridge read/write device. Once properly positioned adjacent the read/write device, the plunge mechanism may insert the cartridge into the read/write device for reading or writing of data. When the operation is complete, the control system can actuate the plunge mechanism to remove the cartridge from the read/write device and return the cartridge to the appropriate location in the storage rack.
Some data storage systems may be configured as scaleable, modular units in which multiple autochanger modules, each having one or more read/write devices for example, can be connected to incrementally expand the total system storage capacity. In some configurations, multiple autochanger modules can be interconnected in a vertical stack. In a particular example, multiple autochanger modules may use a single picker assembly that can move vertically between the autochanger modules as well as horizontally within a single autochanger module. In this manner, the picker assembly may access a data cartridge from any autochanger module and access data from the cartridge from any read/write device in the stack of autochanger modules. Usage of a stack of autochanger modules increases total storage and the total number of cartridge read/write devices that can be simultaneously accessed.
In comparison to multiple individual autochangers connected over a network, a stacked autochanger configuration reduces cost since resources can be reduced to a single picker mechanism and a single housing. Similarly, a controller can perform all management functions by addressing a single device rather than multiple devices, enabling all read/write devices in the stack access to any data cartridge from any level.
A data storage system may use a mailslot for accessing data cartridges. The mailslot is a set of one or more slots allocated for accessing data cartridges. Typically, the mailslot resides at a fixed location in a data storage system. In one example, the mailslot resides at the top level of an autochanger. For a large data storage library, a mailslot at the top level is nonergonomic and may require a user to strain to reach mailslot cartridges. In some cases, a user or administrator may wish to change the location of a mailslot to a more convenient location. Some systems do not allow movement of the mailslot to a more suitable location. Other systems may allow configuration to change the location of the mailslot but the configuration process typically is time consuming and inconvenient, and a user may forget or be uncertain as to the mailslot position.